FRG: Spin and Valley Measurements in Silicon Quantum Devices

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

****NON-TECHNICAL ABSTRACT**** Modern electronic devices work by controlling the location and motion of electrons through semiconductors. Past and current devices work with relatively large numbers of electrons at a time, but there is a continuing drive towards smaller and smaller devices, including those that control and manipulate one electron at a time. In such one-electron devices, the role of quantum mechanics is especially important and potentially useful. Materials properties are important in enabling such devices, and silicon has especially useful characteristics. Fabrication of silicon devices in which individual electrons can be controlled and manipulated has recently been achieved. This project will optimize, characterize, and further develop these materials and devices with the aim of enabling potentially transformative applications in which quantum mechanics is a critical factor. One such application is the quantum computer, which promises to be much more powerful than the classical computers used today. Graduate students participating in this project will obtain valuable interdisciplinary training. In addition, the project will involve the creation of a new workshop for high school teachers, to provide the necessary background for understanding the operation and functionality of modern nanodevices, including the role of quantum mechanics. This award receives support from the Divisions of Materials Research and Physics, as well as the Office of Multidisciplinary Activities. ****TECHNICAL ABSTRACT**** Research has shown that gated quantum dots in semiconductors can be tuned to contain a controllable number of electrons, and that number can be monitored noninvasively by using integrated charge sensors. Quantum dots in silicon are of particular interest because the electron spin coherence times in silicon quantum dots containing only a few electrons are expected to be quite long ? a feature that may be useful for storing and manipulating quantum information. This project focuses on the fundamental role of materials properties on the coherence and control of spins in silicon/silicon-germanium quantum dots. In addition to research on the manipulation of spin and the measurement of spin coherence times, this project will focus on the design, simulation, fabrication, and measurement of silicon/silicon-germanium quantum devices to study the physics of the valley degree of freedom and its interaction with spin. Students participating in this project will obtain valuable interdisciplinary training. The project also involves the creation of a new workshop for high school teachers. The workshop is designed to provide the necessary context for understanding the basic operation and functionality of modern nanodevices, particularly the role of quantum mechanics. The workshops will be accomplished in conjunction with physics outreach specialists at UW-Madison. The project receives support from the Divisions of Materials Research and Physics, as well as the Office of Multidisciplinary Activities.